<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <!-- 连接式引入 -->
    <!-- <link rel="stylesheet" href="./外部引入css.css"> -->
    <style>
        /* @import url("./外部引入css.css"); */
    </style>
</head>
<body>
    <h1>
        我是外部引入CSS
    </h1>
</body>
</html>